Integrated circuit (“ICs”) packages provide mechanical and electrical connections between micron and sub-micron scale circuits defined on an IC die (a “chip”) and a printed circuit board (“PCB”) such as the motherboard of a computer. The IC packages define many of the individual components that are incorporated within circuit boards inside electronic products such as a computer.
As new generations of electrical consumer products are developed, there is a growing need to improve the functionality, performance, reliability, and manufacturing robustness of IC packages. Additionally, miniaturization of handheld devices such as cell phones imposes restrictions on the size and thickness of the package. In general, the goal is to economically produce a chip-scale package (CSP) of the smallest size possible while maintaining a very high performance level.
Conventionally, IC packages are multilayered structures, typically incorporating metal pins (“leads”) that provide a path for electrical power and signal transfer between the IC die and an external device and an encapsulant, such as a molding compound, encapsulating the electrical components. Leadless packages have external contact terminals or pads formed directly on the surface of the package. The encapsulant provides electrical isolation between the leads or external contact terminals, and protects the IC die and internal electrical connections from environmental and mechanical disruptions.
A conventional IC package is fabricated by mounting an IC die onto a paddle of a leadframe (“die-bonding”), electrically connecting the IC die on the paddle to inner leads using thin metal wires (“wire-bonding”), encapsulating a predetermined portion of the assembly containing the IC die, inner leads, and bond wires, with an epoxy resin to form a package body (“molding”), and separating each assembly as individual, independent chip scale packages (“singulation”).
The IC packages, thus manufactured, are then mounted by matching and soldering the external leads or contact pads thereof to a matching pattern on a printed circuit board, to thereby enable power and signal input/output (“I/O”) operations between the semiconductor devices in the packages and the circuit board.
“Flip-chip” technology, as originating with controlled-collapse chip connection is an example of an assembly and packaging technology that results in an IC die being oriented substantially parallel to a carrier substrate, such as a printed circuit board. In flip-chip technology, the bond pads or contact pads of an IC die are arranged in an array over a major surface of the semiconductor device. Flip-chip techniques are applicable to both bare and packaged IC dies. A packaged flip-chip type IC die, which typically has solder balls arranged in a so-called “ball grid array” (BGA) connection pattern, typically includes an IC die and a carrier substrate, which is typically termed an “interposer.” The interposer may be positioned adjacent either the back side of the semiconductor die or the active (front) surface thereof.
There is an on-going need to integrate more functionality and to decrease package thickness and footprint while operating at high circuit speeds. These requirements are addressed using leadless packages with a high density of contact terminals. Thus, the packages must be designed for reliability and must have excellent electrical contact characteristics between the external contact terminals or pads and the printed circuit board. It is increasingly difficult to obtain these levels of package specifications without experiencing contact terminal delamination or signal degradation from poor contacts between the IC package and the printed circuit board.
Thus, a need still remains for IC packaging systems that improve the functionality, performance, reliability, and manufacturing robustness of electronic components. In view of the contact failures and contact surface delamination problems observed in industry, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures, adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.